The overall objective of this proposed research is to isolate and chemically characterize the antitumor active components of Mycobacterium bovis BCG cell walls. It is known that these components can be removed from the cell wall by extraction with a solvent system specific for lipopolysaccharides, a polymer not previously known to be present in the bacteriums cell wall. This author has recently described the presence of a previously unknown lipopolysaccharide in mycobacterial cell walls, which suggests that these molecules may play a very important role in the development of antitumor immunity. The objectives of this proposed research are 1) to purify the antitumor active components of BCG and determine their composition, 2) to purify the newly discovered lipopolysaccharide from BCG and M. phlei and determine their composition, 3) to structurally characterize the antitumor active components of BCG cell walls, 4) to structurally characterize the newly discovered lipopolysaccharide, and 5) to investigate the immunological properties of these cell wall components. Purification of these components will involve various extraction prodecures, gel column chromatography and ion exchange column chromatography, and their characterization will utilize classical as well as newly developed techniques of lipopolysaccharide structural analysis. Their immunological characterization will involve a determination of their antigenicity, adjuvant activity, and ability to act in tumor suppression and regression.